Rotary pump or motor



July 9, 1963 J. c. MCALVAY 3,096,719

ROTARY PUMP OR MOTOR Filed April 29. 1960 2 Sheets-Sheet 1 MMU/m and Wy@ Arron/5v5.

July 9, 1963 J, C, MoALVAY 3,096,719

ROTARY PUMP 0R MOTOR Filed April 29, 1960 2 vSheets-Sheet 2 7311151.15 26 j/Lgj 64 /6 22 /5 22 -Zzfg7 INVENToIc da/A/ C. Mc/ILVAY United 3,096,719 ROTARY PUMP R MOTOR John C. McAlvay, Racine, Wis., assignor to Webster Electric Company, Racine, Wis., a corporation `of Delaware Filed Apr. 29, 1960, Ser. No. 25,571 18 Claims. (Cl. 10S- 126) The present invention relates to rotary pumps or motors and has for its primary Aobject the provision of a new and improved end loaded gear pump or motor.

It has long lbeen desirable to produce gear pumps having a high volumetric eliiciency and constructed to avoid seizure of the gears against `adjacent end faces of the gear chamber. Despite efforts in this direction, difficulties have been encountered, particularly as a result of demands for higher pressures. The use of quick starting motors has also added to the diiiculties.

It is an object of the present invention to provide a new and improved gear pump capable of generating high pressures, which can be quickly started and which can be made simply and will operate with satisfactory volumetric efficiency.

A further object of the present invention is to provide a new and improved gear pump having end loading means engaging one or both sides of the gears, which may be called a wear plate, capable of substantial 4axial movement and which is forced against the gears by pressure generated by the pump, which pressure is chosen to be less than the pump discharge pressure `and is effectively isolated from the discharge pressure by at least one gear tooth so as to prevent pressure surges from acting on the wear plate or plates.

A further object of the present invention is the pro- `vision of a new and improved pump of the character set gears, spacer plates at each side of the gear plate and each having a generally elliptical opening somewhat larger ythan that in said -gear plate, and opposed end plates abutted against the spacer plates. The housing has inlet and discharge passages leading to gears at inlet and discharge areas. The gears have oppositely extending shafts and the end plates having openings for receiving the ends of the shafts. Relatively thin wear plates are disposed at opposite sides of and abut against the side faces of the gears. The wear plates have shapes corresponding to the openings in the spacer plates and have openings for the shafts and openings of the same size as and aligned with the inlet and discharge passages. The wear plates are `of a size such that their peripheral side portions abut against the gear plates and their peripheral edges are spaced from the opening defining edges of the spacer plates to define a seal receiving space. The wear plate thicknesses are substantially less than the thicknesses of the spacer plates whereby the wear plates have substantial freedom lfor movement toward the end plates and pressure chambers are provided at the sides of the wear plates adjacent the end plates. Resilient sealing gaskets surround the peripheral edges of each of the wear plates.

The gaskets have short axially disposed iianges interposed between the peripheral side portions of the wear plates and adjacent portions of .the end plates, whereby axial `movement of the wear plates is permitted. The end plates have annular resilient sealing means located therein abut- 3,696,719 Patented July 9, 1963 "ice ted against both the end plates and wear plates around the discharge passage openings in the latter, thereby to seal off discharge pressures from the said pressure chambers. The end plates also have resilient sealing means located therein and abutting against the end plates and wear plates and defining a pressure area surrounding the said disch-arge passage and extending toward the inlet passageway to slightly beyond a plane normal to a line passing through the inlet and outlet passageways and passing through the axes of rotation of the gears. A pair of openings are provided in each of said wear plates, these openings being similarly located relative to the gears and leading to like pressure regions disposed between the inlet and discharge pressures and isolated at all times from the discharge area -by at least one gear tooth. `If desired, a back up ring may surround the sealing means abutting against the wear plate and defining the pressure area, thereby to render it more effective and durable.

Other objects and advantages of the present invention will become apparent from the ensuing description of a pump constructed in accordance therewith as illustrated in the accompanying drawings, in which:

FIG. l is a top plan view of the pump;

FIG. 2 is a side elevational view of the pump;

FIG. 3 is an enlarged axial cross sectional view taken along the line 3-3 of FIG. l; v

FIG. 4 is a transverse cross sectional view of the pump along the line v4---4 of FIG. 3;

FIG. 5 is a transverse cross sectional View of the pump along the line 5 5 of FIG. 3;

FIG. 6 is a fragmentary enlarged cross sectional view taken along the line 6-6 of FIG. 3 but with the gear pumping elements omitted and illustrating details of the wear plate sealing means;

FIG. 7 is a perspective exploded view of the pump cover plate, spacer and wear plates and associated sealing means;

FIG. 8 is a fragmentary enlarged cross sectional view .along the line 8 8 of FIG. 4;

FIG. 9 is a view similar to FIG. 8 illustrating a modified form of construction in which the sealing ring has a back up ring associated with, it, the view illustrating the parts when not under pressure;

FIG. 10 is a view similar `to FIG. 9 illustrating the parts under pressure; and

BIG. 11 is a view similar to FIG. 8 of a modified construction.

Referring now to the drawings, the present invention is illustrated in connection with a gear pump indicated as a whole by reference character 10. It should be understood that the invention may be utilized in connection with a gear motor and features may be utilized in pumps and motors of types other than the gear type.

The pump includes a pair of intermeshing gears 12 and 14 mounted within a housing 16. The housing comprises a gear plate 18 having an opening 20` comprising intersecting circular cavities 20A and 20B and configured closely to receive the gears. The gear plate 1S is of a thickness corresponding to that of the gears and, if anything, slightly thicker. Relatively thin spacer plates 22 are disposed at opposite sides of the gear plate and they are each provided with a generally elliptical opening 24 (see especially FIG. 7) somewhat larger than the opening 20 in the gear plate. The housing is completed by the opposed end plates 26 and 28 abutted against the spacer plates and having generally planar faces 26A and 2SA facing toward the gears. The location of the spacer plates between the end plates and gear plate provides pressure chambers 30 and 32 at opposite sides of the gears in which are mounted relatively thin wear plates 34 and 36 abutting against the opposite sides of the gears and to which further reference will shortly be had. The spacer plates are thicker than the wear plates by about five percent of the gear plate thickness.

The lspacer rings 22 may be omitted if desired and be replaced by integral portions of the gear or end plates.

The gear 112 has oppositely extending integral tubular shaft portions 12A drivingly connected to a drive shaft 35 by a splined connection. The shaft is journalled in needle bearing structures 38 mounted in a recess 40 in end plate 2S and in a bore 42 in end plate 26. The shaft 35 is journalled in ball bearings 44 mounted in a bore 46 communicating with bore `42. The bearings 44 are held in place by an annular cap 48 surrounding the `shaft and having a shaft seal 50.

The gear 14 has oppositely extending shaft portions 14A mounted in needle bearings 3S in bores 52 and 54 in end plates 26 and`28, respectively. The shaft has a passageway 56 through its interconnecting bores 52 and 54. They are connected by passageway 58 in end plate 26, to bore 46 whereby shaft leakage is conducted to bore 52 and it and gear leakage are conducted to bore 54 through passage S6. From bore 54, the leakage uid is conducted by passageway 60 (see FIG. 4) to the inlet of the pump. Recess 40 is similarly connected to the pump inlet by a passageway 62 (see FIG. 4).

The various parts of the pump housing are held in assembled relation by suitable means such as the bolts 64.

The pump is provided with Kan inlet passageway 66 in end plate 28 having a horizontal laterally extending part 66A and an axially extending part 66B extending to face 28A and communicating with the low pressure inlet region 70 of the gear chamber 20 through an opening 72 in wear plate 34.

The pump has a high pressure outlet or discharge pas' sageway 7 4 with a lateral portion 74A and an axial portion 74B aligned with an opening 76- in the wear plate 34 and leading to the high pressure region 78 of the pump chamber.

The wear plates 34 and 36 constitute end loading means for the sides of the gears and they are constructed and arranged and supplied with loading pressures so as to provide -a pump having good volumetric efiiciency and operating characteristics even when operated at high pressures and using motors with quick starting characteristics. The wear plates are generally elliptical in shape, see FIGS. and 7, corresponding in shape to the openings 24 in the spacer plates. They are of a size such that their peripheral portions extend into overlapping abutting relation to the inner edges of the gear plate 18, see particularly FIGS. 3 and 8, the amou-nt of the overlapping being about 1/s inch. 'Ihe wear plates are sealed at their outer peripheries by an elliptical continuous resilient sealing ring or gasket y80 having a thickened portion 80A effectively between the wear plate and spacer plate and a thinner radially inwardly extending flange 80B clamped between the rear face (the one facing the end plate) of the wear plate and the end plate. 'Ihe arrangement is such that leakage of fluid from the pump housing is prevented While the wear plate has `some freedom of movement `at its periphery and substantial freedom for axial movement. The wear plates have openings 82 through which the gear `shafts extend.

The wear plates have a thickness such that they have some transverse flexibility or give. For a plate having 'a major `axis of about 4.09 inches and a minor axis of about 2.67 inches, -a discharge opening of 3A inch diameter, an inlet opening of 5/8 inch, shaft openings of 2.280 inches, the plate should have a thickness of about .062 inch. Also, the sides of the wear plates facing the gears should lhave a fairly heavy bronze bearing facing and relief passages 83 for relieving gear intertooth pressures may be provided, as indicated in FIGS. 4 and 7. The wear plates, instead of being elliptical may have a configuration substantially like that of the gea-r chamber 20. In this event,

the gaskets 92 would have Ilike configurations, as would the openings Z4 in the spacer plates 22.

The wear plates are each supplied with loading pressure from a source at a pressure less than discharge pressure and isolated from pressure pulsations -at the discharge or outlet, which loading pressure is applied to an area approximating one half the area of the gear chamber and disposed at the outlet, half of the pump.

The wear plates have the previously described pressure chambers 30 and 32 at their back sides. These are divided simply into a high pressure or loading area `84 and a low pressure area 86 (see FIG. 5). The loading area is defined by a pair of endless gaskets 941 and 92. Gasket 90 is a relatively small circular one surrounding the openings 76 in the wear plate and outlet passageway portion 74B in end plate 28. It thus isolates the high pressure discharge area and passageway of the pump from the wear plate pressure chambers. Gasket 92 is of a modified E shape in general configuration and surrounds the outlet side of the pump with a portion 92A above, a portion 92B below and a portion 92C between the gear shafts to slightly beyond -a plane normal to a line passing through the inlet and outlet passageways and also passing through the axes of rotation of the gears 12 and 14. The gaskets are preferably mounted in grooves 94 and 96 in the planar faces 26A and 28A of the respective end plates (see PIG. 7), whereby they are effectively held in place against even high pressures.

The areas inside of gasket 92 and outside of gasket 90 are supplied with a pressure less than discharge pressure through small lopenings and 102 in the wear plates. For a wear plate of dimensions such yas those given above, the openings may be of a diameter of Ma inch. The latter are symmetrically located at the outlet side of the pump and, `as may be noted from FIG. 4, they are located so as to be isolated from -the discharge passage area by at least one gear tooth, these being the teeth 104 and 106 in FIG. 4. As a result, excessively high pressures and pressure pulsations are prevented from acting on the wear plates so that they do not become excessively forced against the gears.

The gasket 92' has its region 92C chosen so as to bring the wear plate in contact with or close clearance relative to the mesh point of the gears. This is important because the isolation of the discharge and inlet ports is little more than ata point and any end clearance leads to excessive leakage. The distance between the arcuate end and inner and outer spans of the gasket is made to correspond as nearly as possible to the depth of the gear teeth. The points 92A and 92B are located beyond the plane passing through the axes of the gears in order to have the sealing gasket bring the wear plate into contact with some of fthe gear teeth on the suction side of the pump. This provides reasonable sealing of the pump for priming under vacuum or low pressure pumping.

The position of the openings 100 and 102 is determined empirically and they are located at an angular position which resulits in high efficiency and at the same time keeps the bearing loads on the gear ends acceptably low.

In View of the high pressures utilized with pumps, the E-sh-aped gasket 92 is subjected to high pressures. To make it more effective a backing ring of rigid or semirigid material may be utilized, .as shown in FIGS. 9* and 10. It is of the same configuration as the gasket 92 and disposed outside the gasket in the groove 96. It has a relatively elongated portion 112 parallel to the side walls of the groove and an inwardly flared portion 114 overlying the rounded wear plate facing portion 92A of the gasket. The portion 112 has a depth less than that of the gasket to provide a space 116 beneath it.

In the absence of pressure, the gasket is as shown in FIG. 9. Under pressure, the gasket forces the back up ring upwardly and also is forced underneath the ring into space 116, whereby the sealing action iS improved and damage to the gasket minimized.

An alternative construction of the sealing gasket 80 is illustrated in FIG. ll. In it the thin ange portion 80B is eliminated, the base portion of the entire gasket being thickened as indicated by reference character 1Z0.

In operation las a pump, t-he shaft 35y is driven as by an electric motor having fast starting characteristics. When placed into operation, liquid is drawn to the suction or low pressure area 'itl of the pump from the inlet 66. Liquid at high pressure is discharged from the high pressure area 78 through the previously described outlet 74.

During starting, it rnay be that the gears heat up more rapidly than the pump housing, which is larger. This, however, has no deleterious effect because the wear plates 34 and 36 are moved axially outwardly and have substantial movement to accommodate expansion of the gears. The wear plates are also maintained against the side `faces of the gears in the area 84, at a pressure proportionate to and :substantially less than discharge pressure. The pressure area 84 is, as previously described, defined by the sealing gaskets 90 and 92, which effectively seal the gears and yet provides for ample movement of the wear plate when required. The pressure within the ring 84 is supplied through the openings lltl and 102 which are at a lower pressure than and isolated from discharge pressure. The pump of the present invention operates satisfactorily with abrupt starts and high ecceleration and with repeated cycling from low to high pressure. The volumetric eiciency is high.

The apparatus described above may be used as a motor. When so used the construction is advantageous in that the location of the openings 100 and 102 results in reduction of pressure applied to the end plates. Were the loading area connected to the pressure port, the pressure required to move the motor load would be applied to the loading area, causing the wear plate to load against the gear ends, further increasing the pressure necessary to turn the rmotor, the degenerative accumulation resulting in the motor failing lto start or being very inefficient. This does not occur with the arrangement of the present invention, as the source of loading pressure is the slip past the irst gear tooth, which slip is at least in part regulated by the loading. The result is that the slip pressure at the holes 161) and 102 is self limiting and `does not cause the braking of the gear.

It should be noted also that, if desired, only one of the wear plates and -associated structures could be used.

While the present invention has been described in connection with details of illustrative embodiments, these details are not intended to be limitative of the invention except as set forth in the accompanying claims.

What is claimed `as new and desired to be secured by United States Letters Patent is:

1. In a rotary machine of the class described, impeller means comprising a pair of intermeshing gears, a housing for said impeller means comprising a rgear plate with an opening configured closely to receive said gears and of a thickness correspondin-g to that of said gears, spacer plates at each side of the gear plate and each having an opening somewhat larger than that in said gear plate, and opposed end plates abutted against said spacer plates, said housing having inlet and discharge passages leading to gears at inl-et and discharge areas, said gears having oppositely extending shafts and the end plates having openings for receiving the ends of the shafts, relatively thin wear plates disposed at opposite sides of and abutting against the side faces of the gears, said wear plates having shapes generally corresponding to the openings in said gear and spacer plates and having openings for said shafts and openings of the same size as and aligned with said inlet and discharge passages, and being of a size so that their peripheral side portions abut against the sides of the gear plates and their peripheral edges are spaced from the opening deining edges of the spacer plates to deiine a seal receiving space, the wear plate thicknesses being substantially less than the thicknesses of said spacer plates whereby the wear plates have :freedom for movement toward the end plates and there are provided pressure chambers at the sides of the wear plates adjacent the end plates, resilient sealing gaskets surrounding the peripheral edges of each of said wear plates and having short axially disposed flanges interposed between the peripheral side portions of the wear plates and adjacent portions of said end plates, said end plates having resilient sealing means located therein abutted against the end plates and wear plates around the openings in the latter aligned with the discharge passage, thereby to seal off discharge pressures from the said pressure chambers, and said end plates having resilient sealing means located therein and abutting against the end plates and wear plates and defining pressure areas surrounding the said first mentioned resilient means and extending toward the inlet passageways somewhat beyond a plane normal to a line passing through the inlet and outlet passageways and also passing through the axes of rotation of the gears, and a pair of small openings .in each of said -wear plates leading to said pressure areas, said openings being similarly located relative to the gears and leading to areas of pressure disposed between the inlet and discharge pressures and isolated at all times from the discharge area by at least one gear tooth.

2. In a rotary machine as claimed in claim l Iwherein the inlet and discharge passages communicate with the gears through the openings in one of said wear plates.

3. In a rotary machine of the class described, impeller means comprising a pair of intermeshing gears, a housing for said impeller means comprising a gear plate with an opening configured closely to receive said gears and of a thickness corresponding to that of said gears, a spacer plate at least at one side of the gear plate and having an opening somewhat larger than that in said gear plate, an end plate abutted against said spacer plate, said housing having inlet and discharge passages leading to gears at inlet and discharge areas, shaft means :for supporting said :gears and having oppositely extending shaft portions and the end plate having an opening for receiving said shaft porions, a relatively thin wear plate disposed at the side of and abutting against the side iaces of the gears, said wear plate having a shape corresponding to the opening in said gear and spacer plates and having openings for said shaft portions and openings of the same size as and aligned with said inlet and discharge passages, and being of a size such that its peripheral side portion abuts against the side of the gear plate and its peripheral edge4 is spaced from the opening defining edge of the spacer plate to dene a seal receiving space, the -wear plate thickness being substantially less than the thickness of said spacer plate Iwhereby the Wear plate has freedom. for movement toward the end plate and there is provided a pressure chamber at the side of the wear plate adjacent the end plate, a resilient sealing gasket surrounding the peripheral edge of said wear plate and having a short axially disposed ange interposed between the peripheral side portion of the `Wear plate and adjacent portion of said end plate, said end plate having resilient sealing means located therein abutted against the end plate and Wear plate around the opening in the latter aligned with the discharge passage, thereby to seal olf discharge pressure from the said pressure chamber, and said end plate having resilient sealing means located therein and abutting against the end plate and wear plate and defining a pressure area surrounding the said rst mentioned resilient means and extending toward the inlet passageway somewhat beyond a plane normal to a line passing through the inlet and outlet passageway and also passing through the axes of rotation of the gears, and a pair of small openings in said wear plate leading to said pressure area, said openings being similarly located relative to the gears and leading to areas of pressure disposed between the inlet and dischange pressures and isolated at all times from th discharge area by at least one gear tooth.

4. In a rotary machine of the class described, impeller means comprising a pair of intermeshing gears, a housing for said impeller means comprising a gear plate with an opening configured closely to receive said gears and of a thickness corresponding to that of said gears, a spacer plate at one side of the gear plate and having an opening somewhat larger than that in said .gear plate, an end plate abutted against said spacer plate, said housing having inlet and discharge passages leading to gears at inlet and discharge areas, shaft means supporting said gears and having oppositely extending shaft portions and the end plate having an opening 'for receiving the shaft portions, a relatively thin 'wear plate disposed at the side of and abutting against the side faces of the gears, said wear plate having a shape corresponding to the opening in said gear and spacer plates and having openings for said shafts and openings of the same size as and aligned with said inlet and discharge passages, and being of a size such that its peripheral side portion abuts against the side of the gear plate and its peripheral edge is spaced from the opening denning edge of the spacer plate to define a seal receiving space, the wear plate thickness being substantially less than the thickness of said spacer plate whereby the wear plate has freedom for movement toward the end plate and there is provided a pressure chamber at the side of the wear plate adjacent the end plate, a resilient sealing gasket surrounding the peripheral edge of said wear plate and having a short axially disposed flange interposed between the peripheral side portion of the wear plate and adjacent portion of said end plate, said end plate having resilient sealing means located therein abutted against the end plate and wear plate around the opening in the latter aligned with the discharge passage, thereby to seal off discharge pressure from the said pressure chamber, and said end plate having resilient sealing means located therein and abutting against the end plate and wear plate and defining a pressure area surrounding the said first mentioned resilient means and extending toward the inlet passageway somewhat beyond a plane normal to a line passing through the inlet and outlet passageway and also passing through the axes of rotation of the gears, and a pair of small openings in said wear plate leading to said pressure area, said openings being similarly located relative to the gears and leading to areas of pressure disposed between the inlet and discharge pressures and isolated at all times from the discharge area by at least one gear tooth.

5. I-n a rotary machine of the class described, impeller means comprising a pair of intermeshing gears, a housing for said impeller means comprising a gear plate with an opening configured closely to receive said gears and of va thickness corresponding to that of said gears, spacer plates at each side of the gear plate and each having an opening somewhat larger than that in said gear plate, and opposed end plates abutted against said spacer plates, said housing having inlet and discharge passages leading to gears at inlet and discharge areas, shaft means with oppositely extending portions supporting said gears and the end plates having openings for receiving said shaft portions, relatively thin wear plates disposed at opposite sides of and abutting against the side lfaces of the gears, said wear plates having shapes generally corresponding to the openings in said gear and spacer plates and having openings for said shaft means and openings of the same size as and aligned with said inlet and discharge passages, and being of a size so that their peripheral side portions abut against the sides of the gear plates and their peripheral vedges are spaced from the opening defining edges of the spacer plates to define a seal receiving space, the wear plate thicknesses being less than the thicknesses of said spacer plates whereby the wear plates have freedom ifor movement toward the end plates and there are provided pressure chambers at the sides of the wear plates adjacent the end plates, resilient sealing gaskets having portions surrounding the peripheral edges of each of said wear plates and having radially short portions interposed between the peripheral side portions of the wear plates and said end plates, saidv end plates having resilient sealing means located therein abutted against the end plates and wear plates around the openings in the latter aligned with the discharge passage, thereby to seal off discharge pressures from the said pressure chambers, and said end plates having resilient sealing means located therein and abutting against the end plates and wear plates and defining pressure areas surrounding the said first mentioned resilient means and extending toward the inlet passageways somewhat beyond a plane normal to a line passing through the inlet and outlet passageways and also passing through the axes of rotation of the gears, and a pair of small openings in each of said wear plates leading to said pressure areas, said openings being similarly located relative to the gears and leading to areas of pressure disposed between the inlet and discharge pressures and isolated at all times from the discharge area by at least one gear tooth.

6. In a rotary machine of the class described, i-mpeller means comprising a pair of intermeshing gears, a housing for said impeller means comprising a gear plate with an opening configured closely to receive said gears and of a thickness corresponding to that of said gears, spacer plates at each side of the gear plate and each having an opening somewhat larger than that in said gear plate, and opposed end plates abutted against said spacer plates, said housing having inlet and discharge passages leading to gears at inlet and discharge areas, shaft means with oppositely extending shaft portions supporting said gears and the end plates having openings for receiving the ends of the shafts, relatively thin wear plates disposed at opposite sides of and abutting against the side faces of the gears, said wear plates having shapes generally corresponding to the openings in said :gear and spacer plates and having openings for said shaft means and openings of the same size as and aligned with said inlet and discharge passages, and being of a size so that their peripheral side portions abut against the sides of the gear plates and their peripheral edges are spaced from the opening defining edges of the spacer plates to define a seal receiving space, the wear plate thicknesses being less than the thicknesses of said spacer plates whereby the wear plates have freedom for movement toward the end plates and there are provided pressure chambers at the sides of the wear plates adjacent the end plates, resilient sealing gaskets having portions surrounding the peripheral edges of each of said wear plates and having radially short portions interposed between the peripheral side portions of the wear plates and said end plates, grooves in said end plates respectively receiving the major portions of said gaskets, said end plates having resilient sealing means located therein abutted against the end plates and wear plates around the openings lin the latter aligned with the discharge passage, thereby to seal ofi discharge pressures from the said pressure chambers, and said end plates having resilient sealing means located therein and abutting against the end plates and wear plates and defining pressure areas surrounding the said first mentioned resilient means and extending toward the inlet passageways somewhat beyond a plane normal to a line passing through the inlet and outlet passageways and also passing through the axes of rotation of the gears, and a pair of small openings in each of said wear plates leading to said pressure areas, said openings being similarly located relative to the gears and leading to areas of pressure disposed between the inlet and discharge pressures and isolated at all times from the discharge area by at least one gear tooth.

7. lIn a rotary machine of the class described, impeller means, a housing for sa-id impeller means, 'a wear plate in said housing having a first side abutting against a side of said impeller means and a second side facing the housing, means including Ia pressure chamber providing for lateral movement of said wear plate relative to the impeller means, high land @low pressure passages passing through said plate to said impeller means, first sealing means in said pressure `chamber between the second side of said plate and said housing surrounding the high pressure passage,

second sealing means in said pressure chamber between the housing and second side of said plate surrounding said first sealing means and bounding an area at the high pressure passage side approximately one half of the size of said impeller means less the area sealed olf by the rst sealing means, and passage means in said plate inside the area bounded by said second sealing means connecting said area to an impeller region where the pressure is more than the inlet pressure and less tha-n the pressure in the high pressure passageway.

8. In a rotary machine of the cl-ass described, impeller means, a housing for said impeller means, a pair of wear plates in said housing each having a tir-st side abutting against a side of said impeller means and a second side iacing the housing, means including pressure chambers associated with the wear plates providing for lateral movement of said wear plates relative to the impeller means, high and low pressure passages passing through -said plates to said impeller means, rst sealing means in said pressure chambers between the second sides of said plates and said housing surrounding the high pressure passage, second sealing means in said pressure chambers between the housing and second -sides of said plates surrounding the high pressure sealing means and bounding areas at the high pressure passage side approximately one half of the size of said impeller means less the area sealed ott by the nrst sealing means, and passage means in said plates inside the areas bounded by said second sea-ling means connecting said areas to an impeller region Where the pressure is more than the inlet pressure and less than the pressure in the high pressure passageway.

9. In a rotary machine of the class described, impeller means, a housing for said impeller means having inlet and outlet passageways leading to said impeller means, a Wear plate in said housing having a hrst side abutting against la side of said impeller means and a second side facing the housing, means including a pressure chamber at the second side of said plate providing for lateral movement of said wear plate relative to the impeller means, said plate having passageway defining means communicating with a high pressure impeller region, first sealing means in said pressure chamber between the second side of said plate and said housing surrounding the passageway defining means communicating with said high pressure impeller region, second sealing means in said pressure chamber between the housing and second side of said plate surrounding the said rst sealing means and bounding an area :at the high pressure impeller side approximately one hal-f of the size `of said impeller means less the area sealed oli? by the iirst sealing means, and passage means connecting the area bounded by said second sealing means to an impeller region where the pressure is more than the inlet pressure and less than the pressure in the high pressure passageway.

10. In a rotary machine of the class described, impeller means, la housing for said impeller means having high and iow pressure regions, a Wear plate in said housing having a rst side abutting against a side of said impeller means and a :second side iacing the housing, means including a pressure chamber at the second side of said plate providing lfor lateral movement of said wear plate relative to the impeller means, sealing means in said pressure chamber between the housing and second side of said plate bounding a single area at the high pressure side approximately one half of the size of said impeller means and passage means connecting the :area bounded by said sealing means to an impeller region where the pressure is more than the inlet pressure and less than the highest pressure in said machine.

11. In a rotary machine of the class described, a housing, impeller means of the gear type in said housing, end loading means -for the impeller means comprising a wear plate and resilient gasket means abutting against and bounding a pressure area on said wear plate, a groove in said housing in which a portion of said gasket is located, anda rel-atively rigid ring encircling the gasket means adjacent the Y 10 wear plate and disposed partially in said groove at the side :of the gasket remote from said pressure area said rin-g engaging both said gasket means and a side oi the groove to prevent extrusion of said gasket means by pressure in said pressure area.

l2. In a machine as claimed in claim 1l in which said ring has a height such that there is provided a space between it and the bottom of the groove.

l13. In a machine as claimed in claim 11 in which said ring has an inwardly and outwardly flared portion abutting the gasket means and -wear plate.

14. In a machine as claimed in claim 11 in which said ning has a height su-ch that there is provided a space between it and the bottom of the groove, said ring also having an inwardly and outwardly ared p-ortion abutting the gasket means and wear plate.

15. In a rotary machine of the class described, impeller means comprising a pair of intermeshing gears, a housing for said impeller means comprising a gear plate with an opening congured closely to receive said gears and of a thickness corresponding to that of said gears, means including an end plate abutted against said gear plate, providing an opening somewhat larger than that in the gear plate, said housing having inlet and discharge passages leading -to the gears at inlet and discharge areas, shaft means for supporting said gears and having oppositely extending shaft portions and the end plate having an opening for receiving said shai'lt portions, a relatively thin Wear plate dispo-sed at the side of and abutting against the side vfaces of the gears, said wear plate having a shape corresponding to the opening in said gear plates and having openings for said shaft portions and openings of the same size as and aligned with said inlet and discharge passages, and being of a size such that its peripheral side portion abuts against the side of the gear plate and its peripheral edge is spaced from the opening deiined by the means including said end plate -to dene a seal receiving space, the wear plate thickness being such that it has freedom for movement toward the end plate and there is provided a pressure chamber at the side of the wear plate adjacent the end plate, means sealing the peripheral edge region of said wear plate, said end plate having resilient sealing means located therein abutted against the end plate and Wear plate around the opening in the latter aligned with the discharge passage, thereby to seal off discharge pressure from the said pressure chamber, and said end plate having resilient seal-ing means located therein and abutting against the end plate and wear plate and defining a pressure area surrounding the said irst mentioned resilient means and extending toward the inlet passageway somewhat beyond a plane normal to a line passing through the inlet and outlet passageway and also passing through the axes of rotation ot" the gears, and a pair of small openings in said wear plate leading to said pressure area, said openings being similarly located relative to `the gears and leading to areas of pressure disposed between the inlet and `discharge pressures and isolated at all times from the discharge area by .at least one gear tooth.

16. In a rotary machine as claimed in claim l5 wherein the inlet land discharge passages communicate with the gears through the openings in said wear pvlate.

17. In a rotary machine of -the class described, gear type impeller means, a housing for said .impeller means having high and low pressure passageways leading to said impeller means, a Wear plate in said housing having a irst side abutting against a side of said impeller means and a second side fac-ing the housing, means including a pressure chamber at the second side of said plate providing for lateral movement of said Wear plate relative to the impeller means, sealing means in said pressure chamber between the housing and second side of said plate bounding a single area at .the high pressure side of the chamber approximately one half of the size of said impeller means, and passage means connecting the area bounded by said sealing means to an impeller region Where the pressure is more than inlet pressure and less than the highest pressure in said machine and isolated at all ltimes from the high pressure passageway by at least one @gear tooth.

18. In a rotary machine of the class desoribechgear type impeller means, a housing for said impeller means having high and low pressure passageways leading to said impeller means, a pair of wear plates in said housing each having a first side abutting against a side of said impeller means and a second side facing the housing, means inoluding a pressure Ichamber `at the second side of each 'of said plates providing for lateral movement of said wear plate relative to the impeller means, sealing means in each said pressure chamber between the housinlg and second side `of said plate bounding a single area at the high pressure side of the chamber approximately one half of the size of said impeller means, and passage means connecting the area bounded by said sealing means to an imp-elder `region where the pressure is more than inlet pressure and less than the highest pressure in said machine and isolated at all times `from the high pressure passageway by at @least one gear tooth.

References Cited in the le of this patent UNITED STATES PATENTS 2,756,681 Oliver July 31, 1956 2,772,638 Nagely Dec. 4, 1956 2,809,592 Miller et al. Oct. 15, 1957 2,816,510 Jarvis Dec. 17, 1957 2,820,416 Compton Ian. 21, 1958 2,824,522 Compton Feb. 25, 1958 2,842,066 Hilton July 8, 1958 2,891,483 Murray et al. June 23, 1959 2,923,248 Hodgson Feb. 2, 1960 2,932,254 Booth etal. Apr. 12, 1960 FOREIGN PATENTS 1,121,180 France Apr. 30:, 1956 

1. IN A ROTARY MACHINE OF THE CLASS DESCRIBED, IMPELLER MEANS COMPRISING A PAIR OF INTERMESHING GEARS, A HOUSING FOR SAID IMPELLER MEANS COMPRISING A GEAR PLATE WITH AN OPENING CONFIGURED CLOSELY TO RECEIVE SAID GEARS AND OF A THICKNESS CORRESPONDING TO THAT OF SAID GEARS, SPACER PLATES AT EACH SIDE OF THE GEAR PLATE AND EACH HAVING AN OPENING SOMEWHAT LARGER THAN THAT IN SAID GEAR PLATE, AND OPPOSED END PLATES ABUTTED AGAINST SAID SPACER PLATES, SAID HOUSING HAVING INLET AND DISCHARGE PASSAGES LEADING TO GEARS AT INLET AND DISCHARGE AREAS, SAID GEARS HAVING OPPOSITELY EXTENDING SHAFTS AND THE END PLATES HAVING OPENINGS FOR RECEIVING THE ENDS OF THE SHAFTS, RELATIVELY THIN WEAR PLATES DISPOSED AT OPPOSITE SIDES OF AND ABUTTING AGAINST THE SIDE FACES OF THE GEARS, SAID WEAR PLATES HAVING SHAPES GENERALLY CORRESPONDING TO THE OPENINGS IN SAID GEAR AND SPACER PLATES AND HAVING OPENINGS FOR SAID SHAFTS AND OPENINGS OF THE SAME SIZE AS AND ALIGNED WITH SAID INLET AND DISCHARGE PASSAGES AND BEING OF A SIZE SO THAT THERIR PERIPHERAL SIDE PORTIONS ABUT AGAINST THE SIDES OF THE GEAR PLATES AND THEIR PERIPHERAL EDGES ARE SPACED FROM THE OPENING DEFINING EDGES OF THE SPACER PLATES TO DEFINE A SEAL RECEIVING SPACE, THE WEAR PLATE THICKNESSES BEING SUBSTANTIALLY LESS THAN THE THICKNESSES OF SAID SPACER PLATES WHEREBY THE WEAR PLATES HAVE FREEDOM FOR MOVEMENT TOWARD THE END PLATES AND THERE ARE PROVIDEZD PRESSURE CHAMBERS AT THE SIDES OF THE WEAR PLATES ADJACENT THE END PLATES, RESILIENT SEALING GASKETS SURROUNDING THE PERIPHERAL EDGES OF EACH OF SAID WEAR PLATES AND HAVING SHORT 